1. Field of the Invention
The present invention, in general relates to trailer hitches and, more particularly, to devices that prevent a trailer from swaying back and forth.
A number of anti-sway devices are currently known. These devices that have certain advantages and disadvantages. The disadvantages, which are discussed briefly hereinbelow, preclude their use in certain instances and prevent optimum results in other situations.
For example, certain currently known anti-sway devices will not function with surge type of brakes.
Other anti-sway types of devices will not function with load distributing types of hitches.
Other anti-sway types of devices require that a particular type of a hitch assembly, such as a receiver hitch, be used.
In addition, other types of anti-sway devices employ a limiting type of geometric design that actually permits the trailer to sway in a particular direction without initially presenting a significant opposing force. Rather, the geometry of certain prior types of devices is such that they become more effective as the trailer sways a greater distance away from normal but they are not especially effective at counteracting initial sway tendencies.
In general, prior types of anti-sway devices are also limited in how they can be attached to trailers, especially trailers with a single tongue.
Accordingly there exists today a need for an anti-sway control device for trailers that is versatile in its ability to attach to both the towing vehicle and the trailer, is suitable for use with surge brakes and weight distributing hitches, and possesses a geometry that provides optimum damping characteristics the moment a trailer begins to sway from normal.
Clearly, such a device would be useful and desirable.
2. Description of Prior Art
Sway control devices are, in general, known. For example, the following patents describe various types of these devices:
U.S. Pat. No. 3,273,911 to Waldie, Sep. 20, 1966; PA1 U.S. Pat. No. 3,294,421 to Mathisen, Dec. 27, 1966; PA1 U.S. Pat. No. 3,502,351 to Gray, Mar. 24, 1970; PA1 U.S. Pat. No. 3,531,139 to Hedgepeth, Sep. 29, 1970; PA1 U.S. Pat. No. 3,787,077 to Sanders, Jun. 22, 1974; PA1 U.S. Pat. No. 3,796,288 to Hollnagel, Mar. 12, 1974; PA1 U.S. Pat. No. 3,837,676 to Rendessy, Sep. 24, 1974; PA1 U.S. Pat. No. 3,957,286 to Goodwin, May 18, 1976; PA1 U.S. Pat. No. 4,306,734 to Swanson, et al, Dec. 22, 1981; and PA1 U.S. Pat. No. 5,660,409 to Hensley, Aug. 26, 1997.
While the structural arrangements of the above described devices, at first appearance, have similarities with the present invention, they differ in material respects. These differences, which will be described in more detail hereinafter, are essential for the effective use of the invention and which admit of the advantages that are not available with the prior devices.